Comparative evaluation of commercially available aflatoxin test methods

Five qualitative methods and 1 quantitative aflatoxin analytical method were compared with the Holaday-Velasco (HV) minicolumn and thin-layer chromatography (TLC) methods for corn in an evaluation involving 4 U.S. Department of Agriculture Federal Grain Inspection Service (USDA-FGIS) laboratories, 1 laboratory at the University of Georgia, and 1 laboratory at the University of Arizona. Samples analyzed included 1 set of artificially contaminated corn containing both aflatoxin B1 and B2 (ratio of B1:B2 of 92:8), 1 set of artificially contaminated corn containing only aflatoxin B1, and 1 set of naturally contaminated corn. Levels of total aflatoxin tested were 0, 10, 15, 20, 25, 30, and 40 ppb. Results of analysis of these samples with each method evaluated are reported. Chi-square analyses indicated that performance of the Afla-20-Cup, Aflatest, EZ-Screen, OXOID, and SAM-A methods was not statistically different from that of the HV minicolumn. Agri-Screen results were not statistically different from those obtained with TLC.